Proliferation Analysis of Multiple Recycling of Re-enriched Reprocessed U Fuel in Commercial Light Water Reactors

<ns3:p> Background Nuclear power offers a reliable and stable source of energy, providing a significant advantage in meeting the growing global energy demand. When managed effectively, nuclear energy has the potential to be a sustainable option for reducing carbon emissions. However, the accumulation of secondary nuclear materials such as plutonium (Pu), minor actinides (MA), and reprocessed uranium (RepU) presents a challenge, as these materials could contribute to proliferation risks. To ensure the long-term sustainability of nuclear energy, careful management, technological intervention, and international safeguards are necessary to mitigate these risks and enhance the overall safety and security of nuclear fuel cycles. Method The advantage of intrinsic features of nuclear fuel when combined with extrinsic measures, could effectively help tackle proliferation risk. This study assesses the proliferation resistance (PR) of re-enriched RepU fuel discharged from a commercial light water reactor (LWR) water-cooled water-moderated energetic reactor (VVER) by estimating the buildup of even-numbered U and Pu isotopes, especially <ns3:sup>236</ns3:sup> U and <ns3:sup>238</ns3:sup> Pu to make the spent nuclear fuel (SNF) less accessible for military purposes due to the nuclear properties of <ns3:sup>238</ns3:sup> Pu, such as high heat generation and spontaneous fission neutron (SFN) generation rates. Results Natural U only contains 0.72 wt% of <ns3:sup>235</ns3:sup> U, 0.0054 wt% of <ns3:sup>234</ns3:sup> U and 99.275 wt% of <ns3:sup>238</ns3:sup> U. During the fuel burnup, in addition to these three isotopes, <ns3:sup>236</ns3:sup> U, considered one of the signature isotopes for the RepU, is produced by the neutron capture of <ns3:sup>235</ns3:sup> U that does not lead to fission, it absorbs a neutron to create, <ns3:sup>237</ns3:sup> U which then beta decays to <ns3:sup>237</ns3:sup> Np, and the production of <ns3:sup>238</ns3:sup> Pu is achieved by transmutation chain reaction initiates from <ns3:sup>235</ns3:sup> U to <ns3:sup>237</ns3:sup> Np through <ns3:sup>236</ns3:sup> U. Multiple recycling of SNF enables <ns3:sup>238</ns3:sup> Pu to increase up to 8% which is effective enough to prevent the spent fuel to be used for military purposes. Conclusion This study demonstrates that multiple recycling of RepU fuel discharged from VVER enhances the proliferation resistance of SNF by increasing even-numbered U and Pu isotopes. </ns3:p>